1. Field of the Invention
The present invention relates to a controller for controlling a motor provided for a vehicle.
2. Description of the Related Art
Electric vehicles such as an electric drive type forklift have a running mechanism section and a lifting mechanism section. The running mechanism section is mainly composed of a running motor, an accelerating mechanism section and a braking mechanism section, which are used for the running of the vehicle. The lifting mechanism section is mainly composed of a lifting motor, an operation lever, and a hydraulic pressure mechanism section, which are used for the lifting operation by the forklift.
The running motor and the working motor are controlled by a controller in which electric circuits are collectively arranged. The controller is composed of a running motor chopper used for the control of the running motor and a lifting motor chopper used for the control of the lifting motor. The chopper is a switching unit to carry out a switching operation. The switching unit is composed of an IGBT (Insulated Gate Bipolar Transistor) device and a diode unit.
FIG. 1 is a plan view of a conventional controller. Referring to FIG. 1, the controller 1 is composed of a control unit 2, a capacitor unit 3, a wiring line group 4 of a first bus bar or a first wiring line 4a and a second bus bar or a second wiring line 4b, a first terminal group 5 and a second terminal group 6.
In FIG. 1, the control unit 2 is arranged in an upper right section. The capacitor unit 3 is arranged in the left side of the control unit 2. The first bus bar 4a and the second bus bar 4b are arranged along the capacitor unit 3. The first terminal group 5 is arranged under the capacitor unit 3 in the figure. The second terminal group 6 is arranged on the right side of the first terminal group 5.
FIG. 2 shows a side view of the conventional controller, when the controller 1 is viewed from the direction of A of FIG. 1. The capacitor unit 3 is arranged along the first bus bar 4a and the second bus bar 4b on a substrate 10 as shown in FIG. 1. The control unit 2 is arranged on the substrate 10. Also, the first terminal group 5 and the second terminal group 6 are arranged on the substrate 10.
FIG. 3 shows a front view of the conventional controller, when the controller is viewed from the direction of B in FIG. 1. Referring to FIG. 3, the control unit 2 is provided onto the substrate 10. The capacitor unit 3 is provided above the substrate 10 through the first bus bar 4a and the second bus bar 4b. The first terminal group 5 and the second terminal group 6 are provided on the substrate 10.
The first terminal group 5 is composed of five terminals. The second terminal group 6 is composed of five terminals. The capacitor unit 3 is composed of six capacitors.
FIG. 4 shows another plan view of conventional controller, when the controller 2 and the capacitor unit 3 are removed from the state shown in FIG. 1. Referring to FIG. 4, on the substrate 10 are arranged the first bus bar 4a, the second bus bar 4b, the first to fourth terminals 5a to 5d, the fifth to ninth terminals 6a to 6e, the first to third IGBT devices 7a to 7c, the first to third diodes 8a to 8c, and the first to fourth terminal receiving planes 9a to 9d. 
The first to third IGBT devices 7a to 7c are provided on the substrate 10. Also, the first to third diodes 8a to 8c are provided on the substrate 10. The first bus bar 4a is connected to one end of each of the first to third diodes 8a to 8c. The first to third IGBT devices 7a to 7c are connected with the second bus bar 4b at one end. The second bus bar 4b is connected with the fourth terminal 5d. The fourth terminal 5d is connected with a negative terminal of a battery (not shown). The other terminal of the first diode 8a is connected with the other terminal of the first IGBT device 7a and the first terminal 5a. The other terminal of the second diode 8b is connected with the other terminal of the second IGBT device 7b and the second terminal 5b. The other terminal of the third diode 8c is connected with the other terminal of the third IGBT device 7c and the third terminal 5c. The first bus bar 4a is connected with the fourth to eighth terminals 6a to 6e. The seventh terminal 6d is connected with the positive terminal of the battery (not shown). The eighth terminal 6e is connected with a power steering motor (not shown).
The first, second and sixth terminals 5a, 5b and 6a are connected with the running motor. The third and fifth terminals 5c and 6c are connected with the working motor (not shown).
In the conventional controller 1, the switching unit, namely, the first to third IGBT devices 7a to 7c and the first to third diodes 8a to 8c share the capacitor unit 3 in common. Therefore, the arrangement position of the capacitors to the switching unit is not always appropriate. When the arrangement position of the capacitors is not appropriate, there is a case that the effect of inductance correction is not sufficiently obtained.
Also, the wiring line route of the bus bar is long and complicated. Therefore, the bus bar needs to be processed or fabricated in accordance with the wiring line route. The fabrication of the bus bar causes cost rise.
Therefore, an object of the present invention is to provide a controller for a motor of a vehicle, in which a capacitor unit can be arranged in an appropriate position to a switching unit.
Another object of the present invention is to provide a controller for a motor of a vehicle, in which it not necessary to prepare a bus bar with a complicated shape.
In order to achieve an aspect of the present invention, a controller for a vehicle motor, includes a switching unit, a capacitor unit, output terminals and wiring lines. The switching unit is provided on a substrate to control power supply to a motor. The capacitor unit is arranged adjacent the switching unit, and is connected to the switching unit. The output terminals are connected to the motor. The wiring lines in the form of elongated bus bars connect the switching unit and the output terminals in a straight line route.
In this case, the switching unit may include switching devices and diodes arranged in alignment with the switching devices, respectively. In this case, the wiring lines, i.e. bus bars, are provided so as to extend in a direction orthogonal to the alignment of the diode and the switching device.
Also, the capacitor unit is provided above the switching unit using brackets. It is desirable that the capacitor unit is provided above the switching unit using brackets. In this case, when the capacitor unit is connected to the switching devices and the diodes, a direction of the brackets is substantially parallel to wiring lines between the switching devices and the diodes.
Also, the controller for the vehicle motor may further include a control circuit formed on an additional substrate which extends upward from the substrate, and the control circuit controls the switching unit.
Also, the capacitor unit is electrically connected with one of the output terminals. Also, the switching unit includes IGBT (Insulated Gate Bipolar Transistor) devices.
Also, the motor is a running motor used for running of the vehicle, and the controller further includes a running control unit for controlling an operation of the running motor. Instead, the motor is a working motor used for a work by the vehicle, and the controller further includes a working control unit for controlling an operation of the working motor.
In order to achieve another aspect of the present invention, a controller of a vehicle motor includes a first switching unit for controlling power supply to a running motor used running of a vehicle; a first capacitor unit arranged adjacent the first switching unit, and connected with the first switching unit; a first group of output terminals to which the running motor is connected; and a first group of wiring lines or bus bars for connecting the first output terminals and the first switching unit in a straight line route. The controller may further include a second switching unit for controlling power supply to a working motor used for work by the vehicle; a second capacitor unit arranged adjacent the second switching unit and connected with the second switching unit; a second group of output terminals to which the working motor is connected; and a second group of wiring lines or bus bars for connecting the second switching unit and the second output terminals in a straight line route.